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Friday, December 30, 2016

The most
frequently asked question asked in 2016 concerned fig trees. Readers wanted to
know why their fig trees did not produce good fruit. Either the fruit dropped
from the tree when they were small or the fruit clung to the tree and never
became large, but remained small, hard and dry.

If not given enough water the fruit will stay small, hard and dry

There
are hundreds of local fig trees that produced fruit consistently for 20 plus
years in our Las Vegas Valley. In most cases, these problems are a human
management problem, not the fault of the tree or the climate.

If not enough water reaches the fruit they are like any other fruit, the fruit remains small. In this case hard and dry as well and inedible.

Fruits of
fig trees are “multiple fruits”, similar in basic structure to fruit of
pineapple and mulberry. Multiple fruits have dozens of flowers produced in a
cluster at the end of a fleshy stem. Each flower produces fruit which expand,
growing into each other, as they get larger. These type of growth produces a
single, large fruit composed of dozens of smaller fruits.

Fig fruit are "multiple fruits" like pineapple or mulberry that have been turned "inside out" with the soft single fruits on the inside and the "core" on the outside

Fig
fruits are strange. When picturing fig fruits, think of a pineapple turned
“inside out”, miniaturized, with “fleshy moist fruits” on the inside and a more
durable “core” on the outside. Pretty cool adaptation for dry, harsh climates.

Figs
originally came from drier parts of Asia, transported to the Middle East,
perhaps over 10,000 years ago. Growing figs by humans predates wheat. Once transported
and grown in deserts, they could no longer survive and produce fruit without
additional water. The tree would survive and grow but could not support a crop
of fruit without additional water. They needed irrigation to be productive.

Fast-forward
to the Mojave Desert and the planting of fig trees. Fig trees do not need much
water to survive year after year. But like any other fruit tree, the tree needs
additional water to support a crop of figs. As the tree gets larger, it needs
more and more water to support this larger tree plus a crop of figs.

Cacti and figs are not a good mix in a desert landscape. The figs need lots of water for fruit production while the cacti don't.

If your
fig fruits are not a good quality it is most likely not enough water. If the
tree is allowed to get big, and they will, add more drip emitters or enlarge
the water basin around the tree. Put a four-inch layer of wood chips around the
base. Or make them smaller.

Fig trees like this 15 year old fig can take some hard pruning to keep its size small.

Fig
trees can be pruned without mercy. They will recover from a stump if they must.
Keeping the tree smaller requires less water for irrigation. Prune them smaller
in December and January but keep some of the growth from 2016 if you want an
early crop of fruit.

Tuesday, December 27, 2016

Q. I planted a 24 inch
boxed "Ped Push" Chinese pistache. After it was in the ground I
removed the nursery planting stake. Now the trunk has a curve in it. Will
properly re-staking help straighten the trunk?

A. The tree requires
staking but not because the trunk is not straight. This will correct itself, on
its own, over time. The tree requires continued staking for other reasons.
Unfortunately, the production nursery that grew this tree did a bad job. The
retail nursery that bought this tree got it at a good price. They are both at
fault because they passed these problems on to you and they knew better!

Looking at the pictures it seems like you did a very good
job planting. I like the idea of the berms around the planted area to hold
water and help push that water deep enough to water the entire roots.

Remember that the berm should be about 4 inches high and
the bottom of the burned area should be as flat as possible or all the water
will build up on the low side resulting in roots that get plenty of water on
the low side but not enough on the high side.

To compensate for uneven soil, the berm must actually be
taller than 4 inches; taller on the low side and shorter on the high side.

I want to point out something to you about the tree and
it will relate back to the staking. Look at the trunk of the tree. Notice that
it does not have a lot of taper to the trunk. What I mean by taper, the trunk
diameter does not change a lot along its entire length.

This is the primary reason it does not stand on its own
very well and will require staking now. In a strong wind, because of the lack
of taper to the trunk, it is very possible this tree could snap in two. If the
trunk had taper, it is much less likely to snap in a strong wind. This has to
do with a lot of engineering mumbo-jumbo.

The reason this tree does not have good trunk taper is
because of how it was grown in the production nursery, not the retail nursery.
But I will fault the retail nursery for buying these types of trees.

They know better but they got a good deal on it and they
pass the savings on to you, hopefully, and you probably bought it because it
was inexpensive compared to others and you didn't know any different.

Trees with a lack of taper on the trunk are grown too
close together in the field, they are pruned incorrectly to encourage height at
the expense of a lack of taper. Then they stake the trees because they cannot
support their own canopy weight because of a lack of taper and this problem is
passed on to you. And I challenge these nurseries to prove me wrong! I know I'm
right and it makes me mad to see these kinds of production practices all
because they want to make a buck.

What can you do to correct this problem? You're going to
have to stake this tree or it will snap in a strong wind. Guaranteed.

Where to stake it is important. The bending and flexing
of the trunk is important in the development of taper. If the tree is staked so
the trunk cannot move back and forth, e.g. flexing and bending, this will
contribute further to this problem.

Secure the trunk to stakes so that the bottom of the
trunk does not move. You do not want the bottom of the trunk going into the
ground to move. You want the top of the tree to flex back and forth, but not
the bottom.

The trunk should be secured high enough so that it does
not snap but the top of the tree can still move. This would be roughly about
halfway up the trunk.

Secondly, if any shoots grow from the trunk, do not prune
them off!! Let them grow until they get about pencil diameter and then prune them
off from the trunk leaving no stubs behind.

New shoots should always be allowed to grow from the
trunk because they help contribute to trunk taper. But remove them when they
get older, always allowing the young ones to remain. Once the tree no longer requires
staking, then keep the trunk clean of any new growth and remove it as soon as
it appears.

If you by any large trees, 15 gallon and above, in the
future I hope you will consider trunk taper or the growth of side shoots along
the trunk when purchasing a tree avoid nurseries that sell inferior plant
quality.

I
will be giving fruit tree pruning classes on both very young trees and
established trees December and January in two locations every Fridays and
Saturdays January 6,7; January 13, 14; January 21, 22; and January 27, 28.

The two locations are:
Master Gardener (University) Orchard in North Las Vegas (Saturdays from 9 am to noon at 4734 Horse Drive, North Las Vegas 89084) and a Private Orchard (young trees only on Fridays at 1 PM downtown near MLK and Bonanza, Las Vegas). Those wishing to attend classes at the private orchard must be approved by sending an email to me at Xtremehorticulture@Gmail.com Attendance there is limited.

Wednesday, December 14, 2016

Q. I have an apple tree that produced some apples but they didn't have any color or taste.

Anna Apple will develop a red blush when they're ripe.

A.If you don't know what apple it is, it must be difficult to know when to
harvest. Apples do not get sweeter once they are removed from the tree.

Even a green apple like Mutsu or Granny Smith will change color from a green apple green to a lighter green color when it matures.

If these apples are getting a blush of red, you might want to wait
longer to harvest them and see if they turn completely red. Seeds inside
the apple turn dark brown when the apple is close to maturity. But the
sugar content may increase if it stays on the tree longer.

Apple seeds turn from white to brown when the apple matures.

Leave a few
on the tree longer and don't harvest them all at once. See if you can
push the sugar content higher by leaving them on the tree longer.

A couple years ago I sent you a picture of a crispy leaf from the tree. The tree did not look too well. Your recommendation was the Eastern Red Bud tree was not acclimated to our environment and to get a Western Red
Bud tree or another tree.

Monday, December 12, 2016

Q. My onions are up from
seed I planted in September and doing great. I planted Candy and Texas Super
Sweet. Both are sweet onions. What should I do now?

Nevada has a great climate for onions, both northern types like this long day Walla Walla grown in Las Vegas, short day like Texas Super Sweet or in between. Spend a little bit more and get some good sweet onions instead of traditional types.

Texas Super Sweet, a short dqy onion that grows well (and tastes great) in Las Vegas

Or this intermediate day onion, Candy

A. Onions are planted from
seed in the fall. September is good timing. Planting them too early in July or
August can cause too much top growth and flowering. The trick is finding that
happy balance between late summer warm weather and cool fall weather. Mid to
late September and early October are usually good months for that in our
climate. Watch local weather to make your final decisions.

Onions can be planted from seed in the fall or transplants an sets in the spring.

Onions seedlings, now called transplants, are dug up
around 1 March and replanted at their correct spacing for bulb development. I
broadcast the seed in the fall so the seed is very close together. I don’t care
about spacing or bulb development at that age. I just want seedlings up high
enough, 6 to 8 inches tall, so I can space them out in the spring 4 inches
apart. If I am shooting for jumbo size, I will plant them 6 inches apart.

If your seedlings are already about 6 inches tall then I
would not fertilize them anymore. However, if they are still small I would
broadcast a high nitrogen fertilizer like 21–0–0 or blood meal (12-0-0) and
water it in. This shot of nitrogen fertilizer will give it a last push of new
growth before it gets cold this winter and they stop growing.

In late February or early March, dig up the seedlings,
careful not to damage the roots, and replant them into rows or blocks depending
on your gardening method. Always replant using a starter fertilizer such as
16-20-0 or a fertilizer with a similar nitrogen to phosphorus (16/20) ratio.
Fertilize onion seedlings once a month, lightly, with a nitrogen fertilizer or
a foliar nitrogen fertilizer.

Q. With cooler weather
here I was wondering if it is safe to cover frost sensitive vegetables with
every day trash bags. I would cut some vent holes in the bags so these
vegetables don’t overheat. I would not keep them covered except the coolest
evenings. I have used burlap but sometimes it is difficult to keep it on some
larger plants.

A. Warm season vegetables
and herbs like tomatoes, basil and peppers get chilling damage below 45F. It isn’t
just freezing temperatures that could be a problem, but “refrigerator
temperatures” could be as well.

Crop covers give about 5 or 6F added protection during freezing weather. And they breathe. And they let in light. And they protect from insects. And.......

Plastic bags won’t give the plants enough protection from
these types of temperatures. Row crop covers (frost covers, frost blankets) that
are draped over the entire row and in contact with the soil are a better
choice. Unlike trash bags, they can be left on top of the plants for several
days at time. Use row crop covers that weigh about 1 ounce per square yard.
They can be used for three or four years, “breathe”, and transmit at least 50%
of the sunlight.

Row crop covers keep temperatures under the cover about 5
to 6° warmer than the outside temperature. Plastic bags won’t do this. Make
sure row crop covers cannot be blown off the plants or the row. Tack or peg the
edges to the soil. Cover the edges with soil.

The added benefit from row crop covers is protection from
insects OUTSIDE the cover. If insects are trapped under the cover that won’t
help protect plants and fruits from being devoured or attacked.

If using some form of pest control, apply it and then
cover these plants soon after the application. Warm temperatures under crop
covers help cool season types of vegetables (lettuce, spinach, broccoli,
carrots) grow a bit faster and protects them from wind damage as well.

Q. I was reading your
article on pruning overgrown oleanders close to the ground to renew them. Our community has a bunch of 10-15 years old
Texas Rangers. They have not been properly maintained. If they were pruned like the oleanders, would
they come back so they don’t have woody stalks at the bottom? My concern is
they may not recover quickly enough and be an eyesore.

A. The big advantage oleander
has when cutting them close to the ground is their rapid growth the following
season. With water and fertilizer applied in the spring, they can be 3 to 5
feet tall the following year after being cut nearly to the ground in late
winter.

Oleander can be cut to the ground, renewal pruning, without problems because it grows back so fast. Different story with Texas Rangers.

This is not true for Texas Ranger. They grow more slowly.
But yes, they will regrow from the base if they are pruned close to the ground.
They may take two seasons to fully recover to your satisfaction. It is up to
you to decide if that is too slow under your circumstances. You may decide to
take them out and replace them instead.

Texas Ranger can be pruned back to the ground but they grow back slowly. This can be a problem if you want a quick recovery.

Remember, the reason that oleanders and Texas Rangers
look so bad in the first place is because of how they were pruned after they
were planted. If they were pruned properly in the first place they would never have
“woody stalks” at the bottom. As long as the same landscape crew is pruning
them, the same problem will appear in about 3 to 5 years of pruning. Then
you’ll be faced with the same problem all over again.

Texas Ranger gives a great floral show most of the year if it is not sheared with a hedge shears.

The proper way to prune Texas Rangers is to remove one or
two of the largest or oldest “stalks” near soil level every 2 to 3 years and
not use a hedge shears. This will cause the shrub to grow from these cut stalks
and fill in from the base. Using a hedge shears and pruning only the top and
sides causes the stalks to become older, woodier and larger in diameter. The
leafy stems and flowers will be found only around the top and sides of the
shrub.

Q. I'd like to trim my
hawthorns because they are too tall. If I do that now in October, will I be
removing the blooms that emerge in the spring?

A.General rule of thumb is if a plant blooms in early
spring (January, February, March and even April) then its flower buds developed
during the previous late summer and fall months. Pruning with a hedge shears,
or cutting off all the new growth with a hand shears, removes flower buds as
well as the spring flower show. Think photinia and pyracantha.

Photinia showing its red leaves and flowers in the spring

If it blooms during the summer, then it produces flowers
on its new growth. In this case, winter pruning will not remove the flower show.
But summer pruning does. Think oleander.

The key to whether you get a spring flower show is really
more about HOW the pruning is done. Trees or shrubs that bloom in the early
spring, if pruned correctly during the winter, will still provide a flower
show.

Pyracantha blooms in the spring

If pyracantha is pruned correctly we will get these red berries for fall and winter color.

Pruning with a hedge shears, unless the plant is part of a
hedge, is never the right way to prune. When pruning shrubs, choose between two
different techniques: renewal pruning or rejuvenation pruning.

Renewal pruning is what is done to Lantana. It is cut to
the ground, leaving one or 2 inches sticking above the soil to provide for new
growth. This type of pruning is done to overgrown, woody oleanders and many
other overgrown shrubs.

Lantana is pruned to the ground every year, renewal pruning, because it will die back in the winter in cold climates

Rejuvenation pruning is selectively cutting 2 to 4 of the
older stems, close to the ground, every 3 to 4 years. This is done to plants
that don’t grow back as quickly as Lantana or oleander.

Look at the base of the shrub. Several older stems were cut to the ground leaving others. This is rejuvenation pruning.

Rejuvenation pruning selectively removes a few of the
oldest stems to make way for younger growth which grows from the base. This
pruning technique always leaves a floral display, regardless of the plant and
when it blooms.

Prune hawthorns now and you will not interfere with the
spring floral display if you use rejuvenation pruning. Pick 3 to 4 of your
tallest stems and prune them back to within a few inches of the ground.

1) Could you identify what kind of plant is in the photo "House
Plant 1"?
2) Could you tell me what may be causing the edges of the leaves on
that plant to be turning brown (House Plant 2)? And is it ok to stake this plant
upright like it is?

3) Could you identify the plant in the photo "House Plant
3"? It was given to my girlfriend as a gift. Is it meant to be an indoor
plant? Any special care involved with it?

4) I have three Rosemary bushes in my yard. One of the three (Rosemary
1) is browning on the tips of the leaves/needles. It's still flowering though.
Any ideas of the cause? "Rosemary 2" shows one of the 'normal'
bushes. The leaves are green and supple but no flowers.

A.

2.

Might be wrong but I think ......

1. Variegated ficus. To confirm ficus (genus, all
plants that are ficus including figs) cut or break a living branch and
white latex should be seen from the broken branch

2. Probably salts or poor drainage. Make sure
the pot drains freely. When watering with tap water make sure at least 20%
of the applied water drains through the container and exits taking excess
salts from tap water is moving and flushed from the soil.

Don’t water too
often. Use a moisture meter to gauge when to water again, lift the pot to
judge its weight or use a pencil inserted into the soil to judge moisture
content.

Dilute tap water with RO or distilled water about 3RO/1tap water to miminize salt damage due to the tap water. It comes from the Colorado River.

3.

3. I think your flowering houseplant your gf
gave you is one of the kalanchoes. They come in dozens of flower colors.
Google it and see if it is or not.

They can handle some dryness but not
too much. Water them and let them get fairly dry before you water again.

To keep the flowers going as long as possible keep the temperature as low
as possible, water regularly, give plenty of sunlight during the winter
and apply small amounts of fertilizer (Miracle Gro, Jobes, Peters) once a
month…LIGHTLY.

4

4. Rosemary should be flowering now or very shortly.
Don’t cut anything back or if you shear or prune it now you will cut off
all the future flowers.

Brown leaf tips with leaves that are otherwise
healthy is a sign of watering too often or poor drainage or both.

If
leaves are discolored and brown tips then it might be a nutrient
deficiency such as iron.

Welcome to Xtremehorticulture

Home. My home base is Las Vegas, Nevada, in the Eastern Mojave Desert. This blog focuses on horticulture in Deserts.

Me. Desert Horticulture is very different from horticulture in wet climates. Very few people talk about it. This blog focuses on it. My experience in horticulture span over 50 years; time as an applied academic and now working as a consultant. This blog shares my experience and advice in Desert Horticulture. Work in Northern, East and Southern Africa, Western and Central Asia and the Middle East have expanded my views on Desert Horticulture.

Questions. I reply to questions sent to me as quickly as possible. Please include pictures. It helps. Unless questions are confidential, I post them on this blog if they add new information.